About Colon Cancer
Colorectal canceris a cancer that starts in the colon or the rectum. These cancers can also be named colon cancer or rectal cancer, depending on where they start. Colon cancer and rectal cancer are often grouped together because they have many features in common.
Cancer starts when cells in the body begin to grow out of control. Cells in nearly any part of the body can become cancer, and can spread to other areas of the body.
How does colorectal cancer start?
Most colorectal cancers begin as a growth called a polyp on the inner lining of the colon or rectum Some types of polyps can change into cancer over the course of several years, but not all polyps become cancer. The chance of changing into a cancer depends on the kind of polyp. The 2 main types of polyps are:
- Adenomatous polyps (adenomas): These polyps sometimes change into cancer. Because of this, adenomas are called a pre-cancerous condition.
- Hyperplastic polyps and inflammatory polyps: These polyps are more common, but in general they are not pre-cancerous.
Other polyp characteristics that can increase the chances a polyp may contain cancer or increase someone’s risk of developing colorectal cancer besides the type include the size (larger than 1cm), the number found (more than two), and if dysplasia is seen in the polyp after it is removed.
Dysplasia, another pre-cancerous condition, is an area in a polyp or in the lining of the colon or rectum where the cells look abnormal (but not like true cancer cells).
If cancer forms in a polyp, it can eventually begin to grow into the wall of the colon or rectum.
The wall of the colon and rectum is made up of several layers. Colorectal cancer starts in the innermost layer (the mucosa) and can grow outward through some or all of the other layers. When cancer cells are in the wall, they can then grow into blood vessels or lymph vessels (tiny channels that carry away waste and fluid). From there, they can travel to nearby lymph nodes or to distant parts of the body.
The stage (extent of spread) of a colorectal cancer depends on how deeply it grows into the wall and if it has spread outside the colon or rectum.
The normal colon and rectum
The colon and rectum are parts of the digestive system, which is also called the gastrointestinal (GI) system (see illustration). The colon and rectum make up the large intestine (or large bowel).
Most of the large intestine is made up of the colon, a muscular tube about 5 feet long. The parts of the colon are named by which way the food matter is traveling.
- The first section is called the ascending colon; it begins with a pouch called the cecum, where undigested food is received from the small intestine, and extends upward on the right side of the abdomen.
- The second section is called the transverse colon because it travels across the body from the right to the left side.
- The third section is called the descending colon because it descends (travels down) on the left side.
- The fourth section is called the sigmoid colon because of its “S” shape; the sigmoid colon joins the rectum, which connects to the anus.
The ascending and transverse sections are collectively referred to as the proximal colon, and the descending and sigmoid colon are referred to as the distal colon.
The colon absorbs water and salt from the remaining food matter after it goes through the small intestine (small bowel). The waste matter that is left after going through the colon goes into the rectum, the final 6 inches of the digestive system, where it is stored until it passes out of the body through the anus.
Types of cancer in the colon and rectum
Adenocarcinomas make up more than 95% of colorectal cancers. These cancers start in cells that make mucus to lubricate the inside of the colon and rectum. When doctors talk about colorectal cancer, they are almost always talking about this type. Some subtypes of adenocarcinoma, such as signet ring and mucinous, may have a worse prognosis (outlook).
Other, less common types of tumors can also start in the colon and rectum. These include:
Carcinoid tumors start from specialized hormone-making cells in the intestine. TGastrointestinal stromal tumors (GISTs) start from specialized cells in the wall of the colon called the interstitial cells of Cajal. Some are non-cancerous (benign). These tumors can be found anywhere in the digestive tract, but are not common in the colon.
Lymphomas are cancers of immune system cells that typically start in lymph nodes, but they can also start in the colon, rectum, or other organs. Information on lymphomas of the digestive system is included in Non-Hodgkin Lymphoma.
Sarcomas can start in blood vessels, muscle layers, or other connective tissues in the wall of the colon and rectum. Sarcomas of the colon or rectum are rare.
Colorectal Cancer Risk Factors
A risk factor is anything that affects your chance of getting a disease such as cancer. Different cancers have different risk factors. Some risk factors, like smoking, can be changed. Others, like a person’s age or family history, can’t be changed.
But having a risk factor, or even many, does not mean that you will get the disease. And some people who get the disease may not have any known risk factors.
Researchers have found several risk factors that might increase a person’s chance of developing colorectal polyps or colorectal cancer.
Colorectal cancer risk factors you can change
Several lifestyle-related factors have been linked to colorectal cancer. In fact, the links between diet, weight, and exercise and colorectal cancer risk are some of the strongest for any type of cancer.
Being overweight or obese
If you are overweight or obese (very overweight), your risk of developing and dying from colorectal cancer is higher. Being overweight (especially having a larger waistline) raises the risk of colon cancer in both men and women, but the link seems to be stronger in men.
Physical inactivity
If you are not physically active, you have a greater chance of developing colorectal cancer. Being more active might help lower your risk.
Certain types of diets
A diet that is high in red meats (such as beef, pork, lamb, or liver) and processed meats (such as hot dogs and some luncheon meats) can raise your colorectal cancer risk.
Cooking meats at very high temperatures (frying, broiling, or grilling) creates chemicals that might raise your cancer risk, but it’s not clear how much this might increase your colorectal cancer risk.
Diets high in vegetables and fruits, and whole grain fibers have been linked with a lower risk of colorectal cancer, but fiber supplements have not been shown to help.
It’s not clear if other dietary components (for example, certain types of fats) affect colorectal cancer risk.
Smoking
People who have smoked for a long time are more likely than non-smokers to develop and die from colorectal cancer. Smoking is a well-known cause of lung cancer, but it is also linked to other cancers, like colorectal cancer. If you smoke and want to know more about quitting.
Heavy alcohol use
Colorectal cancer has been linked to heavy alcohol use. Limiting alcohol use to no more than 2 drinks a day for men and 1 drink a day for women could have many health benefits, including a lower risk of colorectal cancer.
Colorectal cancer risk factors you cannot change
Being older
Your risk of colorectal cancer goes up as you age. Younger adults can get it, but it is much more common after age 50.
A personal history of colorectal polyps or colorectal cancer
If you have a history of adenomatous polyps (adenomas), you are at increased risk of developing colorectal cancer. This is especially true if the polyps are large, if there are many of them, or if any of them show dysplasia.
If you have had colorectal cancer, even though it has been completely removed, you are more likely to develop new cancers in other areas of the colon and rectum. The chances of this happening are greater if you had your first colorectal cancer when you were younger.
A personal history of inflammatory bowel disease
If you have inflammatory bowel disease (IBD), including either ulcerative colitis or Crohn’s disease, your risk of colorectal cancer is increased.
IBD is a condition in which the colon is inflamed over a long period of time. People who have had IBD for many years, especially if untreated, often develop dysplasia. Dysplasia is a term used to describe cells in the lining of the colon or rectum that look abnormal, but are not true cancer cells. They can, however, change into cancer over time.
If you have IBD, you may need to start being screened for colorectal cancer when you are younger and be screened more frequently.
Inflammatory bowel disease is different from irritable bowel syndrome (IBS), which does not increase your risk for colorectal cancer.
A family history of colorectal cancer or adenomatous polyps
Most colorectal cancers are found in people without a family history of colorectal cancer. Still, as many as 1 in 5 people who develop colorectal cancer have other family members who have had it.
People with a history of colorectal cancer in a first-degree relative (parent, sibling, or child) are at increased risk. The risk is even higher if that relative was diagnosed with cancer when they were younger than 45, or if more than one first-degree relative is affected.
The reasons for the increased risk are not clear in all cases. Cancers can “run in the family” because of inherited genes, shared environmental factors, or some combination of these.
Most people with colorectal cancer have no family history of colorectal cancer. Still, as many as 1 in 5 people who develop colorectal cancer have other family members who have been affected by this disease.
Having family members who have had adenomatous polyps is also linked to a higher risk of colon cancer. (Adenomatous polyps are the kind of polyps that can become cancerous.)
If you have a family history of adenomatous polyps or colorectal cancer, talk with your doctor about the possible need to begin screening before age 50. If you have had adenomatous polyps or colorectal cancer, it’s important to tell your close relatives so that they can pass along that information to their doctors and start screening at the right age.
Having an inherited syndrome
About 5% to 10% of people who develop colorectal cancer have inherited gene changes (mutations) that can cause family cancer syndromes and lead to them getting the disease.
The most common inherited syndromes linked with colorectal cancers are familial adenomatous polyposis (FAP) and Lynch syndrome (hereditary non-polyposis colorectal cancer, or HNPCC), but other rarer syndromes can also increase colorectal cancer risk.
Familial adenomatous polyposis (FAP): FAP is caused by changes (mutations) in the APCgene that a person inherits from his or her parents. About 1% of all colorectal cancers are caused by FAP.
In the most common type of FAP, hundreds or thousands of polyps develop in a person’s colon and rectum, usually in their teens or early adulthood. Cancer usually develops in 1 or more of these polyps as early as age 20. By age 40, almost all people with FAP will have colon cancer if their colon hasn’t been removed to prevent it. People with FAP also have an increased risk for cancers of the stomach, small intestines, and some other organs.
- In attenuated FAP, which is a subtype of this disorder, patients have fewer polyps (less than 100), and colorectal cancer tends to occur at a later age.
- Gardner syndrome is a type of FAP that also has non-cancerous tumors of the skin, soft tissue, and bones.
Lynch syndrome (hereditary non-polyposis colon cancer, or HNPCC): Lynch syndrome accounts for about 2% to 4% of all colorectal cancers. In most cases, this disorder is caused by an inherited defect in either the MLH1 or MSH2 gene, but changes in other genes can also cause Lynch syndrome. These genes normally help repair DNA that has been damaged.
The cancers in this syndrome develop when people are relatively young. People with Lynch syndrome can have polyps, but they tend to only have a few, not hundreds as in FAP. The lifetime risk of colorectal cancer in people with this condition may be as high as 80%, but this depends on which gene is affected.
Women with this condition also have a very high risk of developing cancer of the endometrium (lining of the uterus). Other cancers linked with Lynch syndrome include cancer of the ovary, stomach, small intestine, pancreas, kidney, brain, ureters (tubes that carry urine from the kidneys to the bladder), and bile duct.
Turcot syndrome: This is a rare inherited condition in which people have a higher risk of adenomatous polyps and colorectal cancer, as well as brain tumors. There are actually 2 types of Turcot syndrome:
- One is caused by gene changes similar to those seen in FAP, in which cases the brain tumors are medulloblastomas.
- The other is caused by gene changes similar to those seen in Lynch syndrome, in which cases the brain tumors are glioblastomas.
Peutz-Jeghers syndrome: People with this inherited condition tend to have freckles around the mouth (and sometimes on their hands and feet) and a special type of polyp called hamartomas in their digestive tracts. These people are at a much higher risk for colorectal cancer, as well as other cancers, and they usually are diagnosed at a younger than usual age. This syndrome is caused by mutations in the STK11 (LKB1) gene.
MUTYH-associated polyposis: People with this syndrome develop colon polyps that will almost always become cancerous if the colon is not watched closely with regular colonoscopies. These people also have an increased risk of cancers of the small intestine, skin, ovary, and bladder. This syndrome is caused by mutations in the MUTYH gene (which is involved in “proofreading” the DNA to fix any mistakes) and often leads to cancer at a younger age.
Since many of these syndromes above are associated with colorectal cancer at a young age and also linked to other types of cancer, identifying families with these inherited syndromes is important. It lets doctors recommend specific steps such as screening and other preventive measures when the person is younger. Information on risk assessment, and genetic counseling and testing for these syndromes can be found in Genetic Testing, Screening, and Prevention for People with a Strong Family History of Colorectal Cancer.
Your racial and ethnic background
African Americans have the highest colorectal cancer incidence and mortality rates of all racial groups in the United States. The reasons for this are not yet understood.
Jews of Eastern European descent (Ashkenazi Jews) have one of the highest colorectal cancer risks of any ethnic group in the world.
Having type 2 diabetes
People with type 2 (usually non-insulin dependent) diabetes have an increased risk of colorectal cancer. Both type 2 diabetes and colorectal cancer share some of the same risk factors (such as being overweight and physical inactivity). But even after taking these factors into account, people with type 2 diabetes still have an increased risk. They also tend to have a less favorable prognosis (outlook) after diagnosis.
Factors with unclear effects on colorectal cancer risk
Night shift work
Some studies suggest working a night shift regularly may increase the risk of colorectal cancer. It is thought this might be due to changes in levels of melatonin (a hormone that responds to changes in light) in the body. More research is needed.
Previous treatment for certain cancers
Some studies have found that men who survive testicular cancer seem to have a higher rate of colorectal cancer and some other cancers. This might be because of the treatments they have received such as radiation therapy.
Several studies have suggested that men who had radiation therapy to treat prostate cancer might have a higher risk of rectal cancer because the rectum receives some radiation during treatment. Most of these studies are based on men treated in the 1980s and 1990s, when radiation treatments were less precise than they are today. The effect of more modern radiation methods on rectal cancer risk is not clear.
About Kidney Cancer
Kidney cancer is a cancer that starts in the kidneys. Cancer starts when cells in the body begin to grow out of control. Cells in nearly any part of the body can become cancer, and can spread to other areas of the body.
About the kidneys
To understand more about kidney cancer, it helps to know about the kidneys and what they do.
The kidneys are a pair of bean-shaped organs, each about the size of a fist. They are attached to the upper back wall of the abdomen. One kidney is just to the left and the other just to the right of the backbone. The lower rib cage protects the kidneys.
Small glands called adrenal glands sit above each of the kidneys. Each kidney and adrenal gland is surrounded by fat and a thin, fibrous layer known as Gerota’s fascia.
The kidneys’ main job is to filter the blood coming in from the renal arteries to remove excess water, salt, and waste products. These substances become urine. Urine leaves the kidneys through long slender tubes called ureters, which connect to the bladder. The place where the ureter meets the kidney is called the renal pelvis. The urine is then stored in the bladder until you urinate (pee).
The kidneys also have other jobs:
- They help control blood pressure by making a hormone called renin.
- They help make sure the body has enough red blood cells by making a hormone called erythropoietin. This hormone tells the bone marrow to make more red blood cells.
Our kidneys are important, but we actually need less than one complete kidney to function. Many people in the United States are living normal, healthy lives with just one kidney.
Some people do not have any working kidneys at all, and survive with the help of a medical procedure called dialysis. The most common form of dialysis uses a specially designed machine that filters blood much like a real kidney would.
Renal cell carcinoma
Renal cell carcinoma (RCC), also known as renal cell cancer or renal cell adenocarcinoma, is by far the most common type of kidney cancer. About 9 out of 10 kidney cancers are renal cell carcinomas.
Although RCC usually grows as a single tumor within a kidney, sometimes there are 2 or more tumors in one kidney or even tumors in both kidneys at the same time.
There are several subtypes of RCC, based mainly on how the cancer cells look under a microscope. Knowing the subtype of RCC can be a factor in deciding treatment and can also help your doctor determine if your cancer might be due to an inherited genetic syndrome.
Clear cell renal cell carcinoma
This is the most common form of renal cell carcinoma. About 7 out of 10 people with RCC have this kind of cancer. When seen under a microscope, the cells that make up clear cell RCC look very pale or clear.
Papillary renal cell carcinoma
This is the second most common subtype – about 1 in 10 RCCs are of this type. These cancers form little finger-like projections (called papillae) in some, if not most, of the tumor. Some doctors call these cancers chromophilic because the cells take in certain dyes and look pink under the microscope.
Chromophobe renal cell carcinoma
This subtype accounts for about 5% (5 cases in 100) of RCCs. The cells of these cancers are also pale, like the clear cells, but are much larger and have certain other features that can be recognized.
Rare types of renal cell carcinoma
These subtypes are very rare, each making up less than 1% of RCCs:
- Collecting duct RCC
- Multilocular cystic RCC
- Medullary carcinoma
- Mucinous tubular and spindle cell carcinoma
- Neuroblastoma-associated RCC
Unclassified renal cell carcinoma
Rarely, renal cell cancers are labeled as unclassified because the way they look doesn’t fit into any of the other categories or because there is more than one type of cell present.
Other types of kidney cancers
Other types of kidney cancers include transitional cell carcinomas, Wilms tumors, and renal sarcomas.
Transitional cell carcinoma
Of every 100 cancers in the kidney, about 5 to 10 are transitional cell carcinomas (TCCs), also known as urothelial carcinomas.
Transitional cell carcinomas don’t start in the kidney itself, but in the lining of the renal pelvis (where the urine goes before it enters the ureter). This lining is made up of cells called transitional cells that look like the cells that line the ureters and bladder. Cancers that develop from these cells look like other urothelial carcinomas, such as bladder cancer, under the microscope. Like bladder cancer, these cancers are often linked to cigarette smoking and being exposed to certain cancer-causing chemicals in the workplace.
People with TCC often have the same signs and symptoms as people with renal cell cancer − blood in the urine and, sometimes, back pain.
These cancers are usually treated by surgically removing the whole kidney and the ureter, as well as the portion of the bladder where the ureter attaches. Smaller, less aggressive cancers can sometimes be treated with less surgery. Chemotherapy (chemo) is sometimes given before or after surgery, depending on how much cancer is found. The chemo given is the same as that used for bladder cancer. It’s important to talk with your doctor to be aware of your options and the benefits and risks of each treatment.
About 9 out of 10 TCCs of the kidney are cured if they are found at an early stage. The chances for cure are lower if the tumor has grown into the ureter wall or main part of the kidney or if it looks more aggressive (high grade) when seen under a microscope.
After treatment, follow-up visits to your doctor for monitoring with cystoscopy (looking into the bladder with a lighted tube) and imaging tests are very important because TCC can come back in the bladder, as well as other places in the body.
Wilms tumor (nephroblastoma)
Wilms tumors almost always occur in children. This type of cancer is very rare among adults.
Renal sarcoma
Renal sarcomas area rare type of kidney cancer that begin in the blood vessels or connective tissue of the kidney. They make up less than 1% of all kidney cancers.
Benign (non-cancerous) kidney tumors
Some kidney tumors are benign (non-cancerous). This means they do not metastasize (spread) to other parts of the body, although they can still grow and cause problems.
Benign kidney tumors can be treated by removing or destroying them, using many of the same treatments that are also used for kidney cancers, such as surgery, radiofrequency ablation, and arterial embolization. The choice of treatment depends on many factors, such as the size of the tumor and if it is causing any symptoms, the number of tumors, whether tumors are in both kidneys, and the person’s general health.
Renal adenoma
Renal adenomas are the most common benign kidney tumors. They are small, slow-growing tumors that are often found on imaging tests (such as CT scans) when the doctor is looking for something else. Seen with a microscope, they look a lot like low-grade renal cell carcinomas.
In rare cases, tumors first thought to be renal adenomas turn out to be small renal cell carcinomas. Because they are hard to tell apart, suspected adenomas are often treated like renal cell cancers.
Oncocytoma
Oncocytomas are benign kidney tumors that can sometimes grow quite large. As with renal adenomas, it can sometimes be hard to tell them apart from kidney cancers. Oncocytomas do not normally spread to other organs, so surgery often cures them.
Angiomyolipoma
Angiomyolipomas are rare. They often develop in people with tuberous sclerosis, a genetic condition that also affects the heart, eyes, brain, lungs, and skin. These tumors are made up of different types of connective tissues (blood vessels, smooth muscles, and fat). If they aren’t causing any symptoms, they can often just be watched closely. If they start causing problems (like pain or bleeding), they may need to be treated.
What Are the Risk Factors for Kidney Cancer?
A risk factor is anything that affects your chance of getting a disease such as cancer. Different cancers have different risk factors. Some risk factors, like smoking, can be changed. Others, like your age or family history, can’t be changed.
But having a risk factor, or even several risk factors, does not mean that you will get the disease. And some people who get the disease may have few or no known risk factors. Even if a person with kidney cancer has a risk factor, it is often very hard to know how much that risk factor contributed to the cancer.
Scientists have found several risk factors that could make you more likely to develop kidney cancer.
Lifestyle-related and job-related risk factors
Smoking
Smoking increases the risk of developing renal cell carcinoma (RCC). The increased risk seems to be related to how much you smoke. The risk drops if you stop smoking, but it takes many years to get to the risk level of someone who never smoked.
Obesity
People who are very overweight have a higher risk of developing RCC. Obesity may cause changes in certain hormones that can lead to RCC.
Workplace exposures
Many studies have suggested that workplace exposure to certain substances increases the risk for RCC. Some of these substances are cadmium (a type of metal), some herbicides, and organic solvents, particularly trichloroethylene.
Genetic and hereditary risk factors
Some people inherit a tendency to develop certain types of cancer. The DNA in each of your cells that you inherit from your parents may have certain changes that give you this tendency. Some rare inherited conditions can cause kidney cancer. It is important that people who have hereditary causes of RCC see their doctors often, particularly if they have already been diagnosed with RCC. Some doctors recommend regular imaging tests (such as CT scans) to look for new kidney tumors in these people.
People who have the conditions listed here have a much higher risk for getting kidney cancer, although they account for only a small portion of cases overall.
von Hippel-Lindau disease
People with this condition often develop several kinds of tumors and cysts (fluid-filled sacs) in different parts of the body. They have an increased risk for developing clear cell RCC, especially at a younger age. They may also have benign tumors in their eyes, brain, spinal cord, pancreas and other organs; and a type of adrenal gland tumor called pheochromocytoma. This condition is caused by mutations (changes) in the VHL gene.
Hereditary papillary renal cell carcinoma
People with this condition have a tendency to develop one or more papillary RCCs, but they do not have tumors in other parts of the body, as is the case with the other inherited conditions listed here. This disorder is usually linked to changes in the MET gene.
Hereditary leiomyoma-renal cell carcinoma
People with this syndrome develop smooth muscle tumors called leiomyomas (fibroids) of the skin and uterus (in women) and have a higher risk for developing papillary RCCs. It has been linked to changes in the FH gene.
Birt-Hogg-Dube (BHD) syndrome
People with this syndrome develop many small benign skin tumors and have an increased risk of different kinds of kidney tumors, including RCCs and oncocytomas. They may also have benign or malignant tumors of several other tissues. The gene linked to BHD is known as FLCN.
Familial renal cancer
People with this syndrome develop tumors called paragangliomas of the head and neck region, as well as tumors known as pheochromocytomas of the adrenal glands and other areas. They also tend to get kidney cancer in both kidneys before age 40. It is caused by defects in the genes SDHB and SDHD.
These gene defects can also cause something called Cowden-like syndrome. People with this syndrome have a high risk of breast, thyroid and kidney cancers.
Hereditary renal oncocytoma
Some people inherit the tendency to develop a kidney tumor called an oncocytoma, which is almost always benign (not cancer).
Other risk factors
Family history of kidney cancer
People with a strong family history of renal cell cancer (without one of the known inherited conditions listed previously) have a higher chance of developing this cancer. This risk is highest in brothers or sisters of those with the cancer. It’s not clear whether this is due to shared genes, something that both people were exposed to in the environment, or both.
High blood pressure
The risk of kidney cancer is higher in people with high blood pressure. Some studies have suggested that certain medicines used to treat high blood pressure may raise the risk of kidney cancer, but it is hard to tell if it’s the condition or the medicine (or both) that may be the cause of the increased risk.
Certain medicines
Phenacetin: Once a popular non-prescription pain reliever, this drug has been linked to RCC in the past. Because this medicine has not been available in the United States for over 20 years, this no longer appears to be a major risk factor.
Diuretics: Some studies have suggested that diuretics (water pills) may be linked to a small increase in the risk of RCC. It is not clear whether the cause is the drugs or the high blood pressure they treat. If you need to take diuretics, don’t avoid them to try to reduce the risk of kidney cancer.
Advanced kidney disease
People with advanced kidney disease, especially those needing dialysis, have a higher risk of RCC. Dialysis is a treatment used to remove toxins from your body if the kidneys do not work properly.
Gender
RCC is about twice as common in men as in women. Men are more likely to be smokers and are more likely to be exposed to cancer-causing chemicals at work, which may account for some of the difference.
Race
African Americans and American Indians/Alaska Natives have slightly higher rates of RCC than do whites. The reasons for this are not clear.
About Multiple Myeloma
What Is Multiple Myeloma?
Cancer starts when cells in the body begin to grow out of control. Cells in nearly any part of the body can become cancer, and can spread to other areas of the body.
Multiple myeloma is a cancer formed by malignant plasma cells. Normal plasma cells are found in the bone marrow and are an important part of the immune system.
The immune system is made up of several types of cells that work together to fight infections and other diseases. Lymphocytes (lymph cells) are the main cell type of the immune system. The major types of lymphocytes are T cells and B cells.
When B cells respond to an infection, they mature and change into plasma cells. Plasma cells make the antibodies (also called immunoglobulins) that help the body attack and kill germs. Lymphocytes are in many areas of the body, such as lymph nodes, the bone marrow, the intestines, and the bloodstream. Plasma cells, however, are mainly found in the bone marrow. Bone marrow is the soft tissue inside some hollow bones. In addition to plasma cells, normal bone marrow has cells that make the different normal blood cells.
When plasma cells become cancerous and grow out of control, they can produce a tumor called a plasmacytoma. These tumors generally develop in a bone, but they are also rarely found in other tissues. If someone has only a single plasma cell tumor, the disease is called an isolated (or solitary) plasmacytoma. If someone has more than one plasmacytoma, they have multiple myeloma.
Multiple myeloma is characterized by several features, including:
Low blood counts
In multiple myeloma, the overgrowth of plasma cells in the bone marrow can crowd out normal blood-forming cells, leading to low blood counts. This can cause anemia – a shortage of red blood cells. People with anemia become pale, weak, and fatigued. Multiple myeloma can also cause the level of platelets in the blood to become low (called thrombocytopenia). This can lead to increased bleeding and bruising. Another condition that can develop is leukopenia – a shortage of normal white blood cells. This can lead to problems fighting infections.
Bone and calcium problems
Myeloma cells also interfere with cells that help keep the bones strong. Bones are constantly being remade to keep them strong. Two major kinds of bone cells normally work together to keep bones healthy and strong. The cells that lay down new bone are called osteoblasts. The cells that break down old bone are called osteoclasts. Myeloma cells make a substance that tells the osteoclasts to speed up dissolving the bone. Since the osteoblasts do not get a signal to put down new bone, old bone is broken down without new bone to replace it. This makes the bones weak and they break easily. Fractured bones are a major problem in people with myeloma. This increase in bone break-down can also raise calcium levels in the blood.
Infections
Abnormal plasma cells do not protect the body from infections. As mentioned before, normal plasma cells produce antibodies that attack germs. For example, if you developed pneumonia, normal plasma cells would produce antibodies aimed at the specific bacteria that were causing the illness. These antibodies help the body attack and kill the bacteria. In multiple myeloma, the myeloma cells crowd out the normal plasma cells, so that antibodies to fight the infection can’t be made. The antibody made by the myeloma cells does not help fight infections. That’s because the myeloma cells are just many copies of the same plasma cell – all making copies of the same exact (or monoclonal) antibody.
Kidney problems
The antibody made by myeloma cells can harm the kidneys. This can lead to kidney damage and even kidney failure.
Monoclonal gammopathy
Having many copies of the same antibody is known as a monoclonal gammopathy. This condition can be found with a blood test. Although people with multiple myeloma have a monoclonal gammopathy, not everyone with monoclonal gammopathy has multiple myeloma. It can also occur in other diseases, such as Waldenstrom macroglobulinemia and some lymphomas. It can also occur in a disorder known as monoclonal gammopathy of undetermined significance (MGUS), whichdoes not cause problems like multiple myeloma does. However, some people with MGUS will eventually go on to develop multiple myeloma or other diseases.
Light chain amyloidosis
Antibodies are made up of protein chains joined together – 2 short light chains and 2 longer heavy chains. In light chain amyloidosis, abnormal plasma cells make too many light chains. These light chains can deposit in tissues, where they build up. This accumulation of light chains can lead to an abnormal protein in tissues known as amyloid. The buildup of amyloid in certain organs can lead them to enlarge and not work well. For example, when amyloid builds up in the heart, it can cause an irregular heart beat and cause the heart to enlarge and get weaker. A weak heart can lead to a condition called congestive heart failure, with symptoms like shortness of breath and swelling in the legs. Amyloid in the kidneys can cause them to work poorly. This may not cause symptoms early on, but the poor kidney function may be found on blood tests. If it gets worse, amyloid in the kidney can lead to kidney failure. Other names for light chain amyloidosis include AL and primary amyloidosis. This is sometimes considered a separate disease from multiple myeloma, but because treatment is often similar to that of myeloma, we will discuss it in this document.
Light chain amyloidosis is only one of the diseases where amyloid builds ups and causes problems. Amyloidosis can also be caused by a genetic (hereditary) disease called familial amyloidosis. Long-standing (chronic) infection and/or inflammation can also cause amyloidosis. This is known as secondary or AA amyloidosis. This document does not talk about these other kinds of amyloidosis.
Monoclonal gammopathy of undetermined significance
In monoclonal gammopathy of undetermined significance (MGUS), abnormal plasma cells produce many copies of the same antibody (a monoclonal antibody protein). However, these plasma cells do not form an actual tumor or mass and do not cause any of the other problems seen in multiple myeloma. MGUS usually does not affect a person’s health. In particular, it doesn’t cause weak bones, high calcium levels, kidney problems, or low blood counts. It’s most often found when a routine blood test finds a high level of protein in the blood and further testing shows the protein is a monoclonal antibody. In MGUS, the number of plasma cells may be increased, but they still make up less than 10% of the cells in the bone marrow.
Some people with MGUS will eventually develop multiple myeloma, lymphoma, or amyloidosis. Each year, about 1% of people with MGUS develops one of these diseases. The risk is higher in people whose protein levels are particularly high. Patients with MGUS don’t need treatment, but they are watched closely to see if they get a disease that does need to be treated, such as multiple myeloma.
Recently, scientists have studied the genes of the plasma cells in patients with MGUS. They found that the genetic make-up of these plasma cells resembles myeloma plasma cells more than it resembles that of normal plasma cells. This suggests that these cells are truly malignant, not just slow growing. Because people with MGUS are generally elderly, they may not live long enough for it to transform into myeloma.
Solitary plasmacytomas
This is another type of abnormal plasma cell growth. Rather than many tumors in different locations as in multiple myeloma, there is only one tumor, hence the name solitary plasmacytoma.
Most often, a solitary plasmacytoma develops in a bone, where it may be called an isolated plasmacytoma of bone. When a plasmacytoma starts in other tissues (such as the lungs or other organs), it is called an extramedullary plasmacytoma. Solitary plasmacytomas are most often treated with radiation therapy. Sometimes surgery may be used for a single extramedullary plasmacytoma. As long as no other plasmacytomas are found later on, the patient’s outlook is usually excellent. However, since many people with a solitary plasmacytoma will develop multiple myeloma, these people are watched closely for signs of this disease.
What Are the Risk Factors for Multiple Myeloma?
A risk factor is anything that changes a person’s chance of getting a disease such as cancer. Different cancers have different risk factors. For example, exposing skin to strong sunlight is a risk factor for skin cancer. Smoking is a risk factor for lung cancer and many other cancers. But risk factors don’t tell us everything. People who have no risk factors can still get the disease. Also, having a risk factor, or even several, does not mean that a person will get the disease.
Scientists have found few risk factors that may affect someone’s chance of getting multiple myeloma.
Age
The risk of multiple myeloma goes up as people age. Less than 1% of cases are diagnosed in people younger than 35. Most people diagnosed with this cancer are at least 65 years old.
Gender
Men are slightly more likely to develop multiple myeloma than women.
Race
Multiple myeloma is more than twice as common in African Americans than in white Americans. The reason is not known.
Radiation
People who were exposed to radiation from an atomic bomb blast had a higher risk of multiple myeloma. Exposure to lower levels of radiation may also increase the risk of multiple myeloma. At most, this accounts for a very small number of cases.
Family history
Multiple myeloma seems to run in some families. Someone who has a sibling or parent with myeloma is 4 times more likely to get it than would be expected. Still, most patients have no affected relatives, so this accounts for only a small number of cases.
Workplace exposures
Studies looking at workplace exposures and multiple myeloma risk have found no clear links.
Obesity
A study by the American Cancer Society has found that being overweight or obese increases a person’s risk of developing myeloma.
Having other plasma cell diseases
Many people with monoclonal gammopathy of undetermined significance (MGUS) or solitary plasmacytoma will eventually develop multiple myeloma.